The MC14500B Industrial Control Unit (ICU) is a

CMOS Complementary metal–oxide–semiconductor (CMOS, pronounced "sea-moss ", , ) is a type of MOSFET, metal–oxide–semiconductor field-effect transistor (MOSFET) semiconductor device fabrication, fabrication process that uses complementary an ...

one-bit

microprocessor A microprocessor is a computer processor (computing), processor for which the data processing logic and control is included on a single integrated circuit (IC), or a small number of ICs. The microprocessor contains the arithmetic, logic, a ...

Motorola Motorola, Inc. () was an American multinational telecommunications company based in Schaumburg, Illinois. It was founded by brothers Paul and Joseph Galvin in 1928 and had been named Motorola since 1947. Many of Motorola's products had been ...

for simple control applications in 1977.

Overview

MC14500B (ICU) is well-suited to the implementation of

ladder logic Ladder logic was originally a written method to document the design and construction of relay logic, relay racks as used in manufacturing and process control. Each device in the relay rack would be represented by a symbol on the ladder diagram w ...

, and thus could be used to replace

relay A relay Electromechanical relay schematic showing a control coil, four pairs of normally open and one pair of normally closed contacts An automotive-style miniature relay with the dust cover taken off A relay is an electrically operated switc ...

systems and

programmable logic controller A programmable logic controller (PLC) or programmable controller is an industrial computer that has been ruggedized and adapted for the control of manufacturing processes, such as assembly lines, machines, robotic devices, or any activity that ...

s, also intended for serial data manipulation. The processor supports 16 commands, operating at a frequency of 1 MHz. The MC14500B unit does not include a

program counter The program counter (PC), commonly called the instruction pointer (IP) in Intel x86 and Itanium microprocessors, and sometimes called the instruction address register (IAR), the instruction counter, or just part of the instruction sequencer, ...

(PC); instead, a clock signal drives a separate PC chip; therefore the size of supported memory is dependent on the implementation of that chip. It was still in production in 1995. The ICU architecture is similar to that of the DEC

PDP-14 The PDP-14 was a specialized computer from Digital Equipment Corporation’s Industrial Products Group designed to replace industrial level relay controls for machinery and machine tools that performed repetitive tasks. It was specifically designed ...

computer.

Developers

The ICU was conceived by Vern Gregory in the mid-1970s while working as an engineer in a marketing / applications group of Motorola Semiconductor Products Sector in Phoenix, Arizona, USA; Brian Dellande originated circuit and sub-routine designs, and co-wrote the manual; Ray DiSilvestro was the bench technician; Terry Malarkey provided management support. In the CMOS Logic Division in Austin, Texas, USA (where it was made) Phil Smith was the chip designer; Mike Hadley provided product applications support.

Derivatives

A form of the design served as an embedded controller in a custom automotive chip made for Nippon Denso by Motorola—Japan. I.P.R.S. Băneasa manufactured a clone of the MC14500B with the designation βP14500 in IIL technology (rather than the original CMOS).

Notable uses

One of the computers known to be based on this processor is the educationa
WDR 1
bit computer (512 bits of RAM, LED, I/O, keyboard). A modern take, in retro style, of a computer based on this processor is th
PLC14500-Nano
It is certified as Open Source Hardwar

so anyone can learn from its design and can freely build it.

References

External links

* * * * * {{Motorola processors Motorola microprocessors Motorola microcontrollers